1. Field of the Invention
The invention relates to the field of telecommunications between users, and more particularly the field of supplying a system with means for extending the concept of the availability of a user of a mobile or fixed network.
2. Description of Related Art
Numerous situations in the world of telecommunications make use of the concept of the presence of a user of a mobile or fixed network.
Such concepts are in widespread use in applications such as Windows Live Messenger, GoogleTalk, AIM, or Pushchat. Those applications make it possible for the presence of a first user to be shown in a list of contacts, thereby enabling contact to be made with that first user if some other user seeing that list of contacts so desires, with the first user's availability being visible in the list.
Such presence defines a logical or physical state of the connection between the user and a network and/or of the user's desire to specify availability. The most frequent states that are determined by systems or indicated by users are the following:                Available        Not connected        Busy        Unavailable.        
Those availability states may be accompanied by messages provided by the user, making it possible to specify a special situation to people consulting that user's status, for example “on holiday” or “driving”.
In more advanced manner, the system may make available a method for indicating a user's preferences for communicating. This enables the user to specify that short message service (SMS) messages are preferred on a mobile telephone while voice type conversations using the Skype application, for example, are preferred on a computer.
That type of operation is particularly well developed by the Pushchat application from the supplier Pushmessenger that enables a user to be connected to the service via a plurality of distinct terminals. U.S. Pat. No. 7,469,045 describes a method of that type.
Very recently, and in particular in association with the appearance of equipment that enables the positions of terminals to be located by the global positioning system (GPS), users of such applications that already make use of presence can also be located and they can communicate their locations to third parties.
The user of one of the above-mentioned applications can thus be informed about the real or chosen state of availability of a given user, with that user's preferences for communication and with that user's location, whether in a fixed situation or a mobile situation.